<template>
  <view class="uni-numbox">
    <view @click="_calcValue('minus')" class="uni-numbox__minus">
      <text class="uni-numbox--text" :class="{ 'uni-numbox--disabled': inputValue <= min || disabled }">-</text>
    </view>
    <input :disabled="disabled" @blur="_onBlur" class="uni-numbox__value" type="number" v-model="inputValue" />
    <view @click="_calcValue('plus')" class="uni-numbox__plus">
      <text class="uni-numbox--text" :class="{ 'uni-numbox--disabled': inputValue >= max || disabled }">+</text>
    </view>
  </view>
</template>
<script>
  /**
   * NumberBox 数字输入框
   * @description 带加减按钮的数字输入框
   * @tutorial https://ext.dcloud.net.cn/plugin?id=31
   * @property {Number} value 输入框当前值
   * @property {Number} min 最小值
   * @property {Number} max 最大值
   * @property {Number} step 每次点击改变的间隔大小
   * @property {Boolean} disabled = [true|false] 是否为禁用状态
   * @event {Function} change 输入框值改变时触发的事件，参数为输入框当前的 value
   */

  export default {
    name: "UniNumberBox",
    props: {
      value: {
        type: [Number, String],
        default: 1
      },
      min: {
        type: Number,
        default: 0
      },
      max: {
        type: Number,
        default: 100
      },
      step: {
        type: Number,
        default: 1
      },
      disabled: {
        type: Boolean,
        default: false
      },
      goodsid: {
        type: Number,
        default: -1
      }
    },
    data() {
      return {
        inputValue: 0
      };
    },
    watch: {
      value(val) {
        this.inputValue = +val;
      },
      inputValue(newVal, oldVal) {
        if (+newVal !== +oldVal) {
          this.$emit("change", newVal, this.goodsid);
        }
      }
    },
    created() {
      this.inputValue = +this.value;
    },
    methods: {
      _calcValue(type) {
        if (this.disabled) {
          return;
        }
        const scale = this._getDecimalScale();
        let value = this.inputValue * scale;
        let step = this.step * scale;
        if (type === "minus") {
          value -= step;
          if (value < (this.min * scale)) {
            return;
          }
          if (value > (this.max * scale)) {
            value = this.max * scale
          }
        } else if (type === "plus") {
          value += step;
          if (value > (this.max * scale)) {
            return;
          }
          if (value < (this.min * scale)) {
            value = this.min * scale
          }
        }

        this.inputValue = String(value / scale);
      },
      _getDecimalScale() {
        let scale = 1;
        // 浮点型
        if (~~this.step !== this.step) {
          scale = Math.pow(10, (this.step + "").split(".")[1].length);
        }
        return scale;
      },
      _onBlur(event) {
        let value = event.detail.value;
        if (!value) {
          this.inputValue = 1;
          return;
        }
        value = +value;
        if (value > this.max) {
          value = this.max;
        } else if (value < this.min) {
          value = this.min;
        }
        this.inputValue = value;
      }
    }
  };
</script>
<style scoped>
  /* #ifdef APP-NVUE */
  /* #endif */

  .uni-numbox {
    /* #ifndef APP-NVUE */
    display: flex;
    /* #endif */
    flex-direction: row;
    height: 35px;
    line-height: 35px;
    width: 120px;
  }

  .uni-numbox__value {
    background-color: #ffffff;
    width: 40px;
    height: 35px;
    text-align: center;
    font-size: 32rpx;
    border-width: 1rpx;
    border-style: solid;
    border-color: #e5e5e5;
    border-left-width: 0;
    border-right-width: 0;
  }

  .uni-numbox__minus {
    /* #ifndef APP-NVUE */
    display: flex;
    /* #endif */
    flex-direction: row;
    align-items: center;
    justify-content: center;
    width: 35px;
    height: 35px;
    /* line-height: $box-line-height;
 */
    /* text-align: center;
 */
    font-size: 20px;
    color: #333;
    background-color: #f8f8f8;
    border-width: 1rpx;
    border-style: solid;
    border-color: #e5e5e5;
    border-top-left-radius: 6rpx;
    border-bottom-left-radius: 6rpx;
    border-right-width: 0;
  }

  .uni-numbox__plus {
    /* #ifndef APP-NVUE */
    display: flex;
    /* #endif */
    flex-direction: row;
    align-items: center;
    justify-content: center;
    width: 35px;
    height: 35px;
    border-width: 1rpx;
    border-style: solid;
    border-color: #e5e5e5;
    border-top-right-radius: 6rpx;
    border-bottom-right-radius: 6rpx;
    background-color: #f8f8f8;
    border-left-width: 0;
  }

  .uni-numbox--text {
    font-size: 40rpx;
    color: #333;
  }

  .uni-numbox--disabled {
    color: #c0c0c0;
  }
</style>
